Determining location of client devices in a distributed antenna system (das) based on detecting received uplink power

ABSTRACT

Embodiments of the disclosure relate to determining location of client devices in a distributed antenna system (DAS) based on detecting uplink received power. In this regard, a client device location system is provided in the DAS to configure each remote unit in the DAS to generate a power-regulated UL communications signal based on an assigned power pattern. If a respective power pattern of a reference signal(s) uniquely identifying a client device corresponds to the assigned power pattern of the remote unit that generates the power-regulated UL communications signal, the client device location system reports the location of the remote unit as the location of the client device in the DAS. Hence, it is possible to locate the client device based on the location of the remote unit, thus providing the location of the client device with higher degree of accuracy.

PRIORITY APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/984,014, filed Dec. 30, 2015, which claims the benefit of priorityunder 35 U.S.C. §119 of U.S. Provisional Application 62/253326, filed onNov. 10, 2015, the content of which is relied upon and incorporatedherein by reference in its entirety.

BACKGROUND

The disclosure relates generally to a distributed antenna system (DAS)and, more particularly, to locating client devices in a DAS.

Wireless customers are increasingly demanding more sophisticatedwireless services, such as context-aware and location-aware wirelessservices. At the same time, some wireless customers use their wirelesscommunication devices in areas that are poorly serviced by conventionalcellular networks, such as inside certain buildings or areas where thereis little cellular coverage. One response to the intersection of thesetwo concerns has been the use of DASs. DASs include remote unitsconfigured to receive and transmit communications signals to clientdevices within the antenna range of the remote units. DASs can beparticularly useful when deployed inside buildings or other indoorenvironments where the wireless communication devices may not otherwisebe able to effectively receive radio frequency (RF) signals from asource.

Many context-aware and location-aware wireless services, such asenhanced 911 (E911) services, rely on accurately detecting the locationsof wireless communication devices. A satellite-based location detectionsystem, such as global positioning system (GPS) in the United States, isunreliable in indoor environments served by the DASs due to the inherentinability of a satellite signal to penetrate obstacles like buildingwalls. Although it may be possible to determine general locations ofwireless communication devices based on base stations in the conventioncellular network, it remains challenging for base stations to pinpointthe locations of the wireless communication devices with higher degreeof accuracy.

No admission is made that any reference cited herein constitutes priorart. Applicant expressly reserves the right to challenge the accuracyand pertinency of any cited documents.

SUMMARY

Embodiments of the disclosure relate to determining location of clientdevices in a distributed antenna system (DAS) based on detecting uplinkreceived power. In this regard, in aspects disclosed herein, a locationof a client device in a DAS can be identified by determining thelocation of a remote unit with which the client device is engaged indownlink (DL) and/or uplink (UL) communications (e.g., exchange ofcontrol messages or traffic). In this regard, in one exemplary aspect, aparticular power pattern can be assigned to remote units that receive ULcommunications signals from client devices in the DAS. A remote unit isconfigured to generate a power-regulated UL communications signal basedon a respective assigned power pattern and respective UL communicationssignals received from client devices engaged in the UL communicationswith the remote unit. The power-regulated UL communications signal isanalyzed in the DAS to determine if the respective assigned powerpattern in the received power-regulated UL communications signal can beassociated with a client device to be located. Thus, the location of theclient device can be known to be within a communication range of theremote unit that has the respective assigned power pattern. The remoteunits in the DAS may each be assigned a unique power pattern or share acommon power pattern, as examples. When the remote units are sharing thecommon power pattern, the remote units can be temporally controlled tocommunicate the power-regulated UL communications signals in the DAS. Bydetermining the location of the client device based on detecting theassigned power pattern associated with the remote unit communicatingwith the client device, it is possible to determine the relativelocation of the client device in the DAS based on the location of theremote unit, thus providing the location of the client device withhigher degree of accuracy.

One embodiment of the disclosure relates to a client device locationidentification system for a DAS. The client device locationidentification system comprises a plurality of remote units in the DAS.Each of the plurality of remote units is configured to receive a ULcommunications signal from the one or more client devicescommunicatively coupled to the DAS. Each of the plurality of remoteunits is also configured to generate a power-regulated UL communicationssignal based on an assigned power pattern. The power-regulated ULcommunications signal comprises one or more reference signals uniquelyidentifying the one or more client devices. The client device locationidentification system also comprises a client device location system.The client device location system is configured to determine theassigned power pattern for each of the plurality of remote units. Theclient device location system is also configured to receive thepower-regulated UL communications signal from each of the plurality ofremote units. The client device location system is also configured todetermine a respective reference signal power pattern and a respectiveclient device identification associated with each of the one or morereference signals comprised in the received power-regulated ULcommunications signal. The client device location system is alsoconfigured to determine whether the respective reference signal powerpattern corresponds to the assigned power pattern of a remote unit thatgenerates the power-regulated UL communications signal.

Another embodiment of the disclosure relates to a method for locatingclient devices in a DAS. The method comprises determining an assignedpower pattern for each of a plurality of remote units in the DAS. Themethod also comprises configuring each of the plurality of remote unitsto generate a power-regulated UL communications signal based on theassigned power pattern. The power-regulated UL communications signalcomprises one or more reference signals uniquely identifying one or moreclient devices. The method also comprises determining a respectivereference signal power pattern and a respective client deviceidentification associated with each of the one or more reference signalscomprised in the power-regulated UL communications signal. The methodalso comprises determining whether the respective reference signal powerpattern corresponds to the assigned power pattern of a remote unit thatgenerates the power-regulated UL communications signal.

Another embodiment of the disclosure relates to a DAS for locatingclient devices. The DAS comprises a central unit communicatively coupledto a communications signal source and a plurality of remote units overat least one communications medium. Each of the plurality of remoteunits is configured to receive a DL communications signal from thecentral unit over the at least one communications medium. Each of theplurality of remote units is also configured to distribute the DLcommunications signal to one or more client devices in the DAS. Each ofthe plurality of remote units is also configured to receive a ULcommunications signal from the one or more client devices. Each of theplurality of remote units is also configured to generate apower-regulated UL communications signal based on an assigned powerpattern. The power-regulated UL communications signal comprises one ormore reference signals uniquely identifying the one or more clientdevices. Each of the plurality of remote units is also configured toprovide the power-regulated UL communications signal to the central unitover the at least one communications medium. The DAS also comprises aclient device location system communicatively coupled to the centralunit and the plurality of remote units. The client device locationsystem is configured to determine the assigned power pattern for each ofthe plurality of remote units. The client device location system is alsoconfigured to receive the power-regulated UL communications signal fromeach of the plurality of remote units. The client device location systemis also configured to determine a respective reference signal powerpattern and a respective client device identification associated witheach of the one or more reference signals comprised in the receivedpower-regulated UL communications signal. The client device locationsystem is also configured to determine whether the respective referencesignal power pattern corresponds to the assigned power pattern of aremote unit that generates the power-regulated UL communications signal.The client device location system is also configured to report alocation of the remote unit that generates the power-regulated ULcommunications signal as a location of a client device having therespective client device identification if the respective referencesignal power pattern is determined to correspond to the assigned powerpattern of the remote unit that generates the power-regulated ULcommunications signal.

Additional features and advantages will be set forth in the detaileddescription which follows and, in part, will be readily apparent tothose skilled in the art from the description or recognized bypracticing the embodiments as described in the written description andclaims hereof, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary and are intendedto provide an overview or framework to understand the nature andcharacter of the claims.

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary distributed antenna system(DAS);

FIG. 2 is a schematic diagram of a client device location identificationsystem that includes a client device location system configured todetermine locations of client devices in a DAS based on detectingassigned power patterns associated with a plurality of remote units inthe DAS;

FIG. 3 is a flowchart of an exemplary client device locationidentification process that can be employed by the client devicelocation identification system of FIG. 2 to determine locations ofclient devices in the DAS;

FIG. 4 is a schematic diagram of an exemplary client device locationidentification system that includes a client device location systemconfigured to determine locations of client devices in a DAS based on aplurality of power-regulated uplink (UL) communications signalsrespectively generated by the plurality of remote units of FIG. 2 basedon a time-division schedule;

FIG. 5 is a diagram providing an exemplary illustration of the clientdevice location system of FIG. 4 determining the locations of clientdevices based on the plurality of power-regulated UL communicationssignals that is respectively generated by the plurality of remote unitsbased on the time-division schedule;

FIG. 6 is a schematic diagram of an exemplary client device locationidentification system that includes a client device location systemconfigured to determine the locations of client devices in a DAS basedon identifying unique power patterns associated with the remote units inpower-regulated UL communications signals generated by the plurality ofremote units of FIG. 2;

FIG. 7 is a schematic diagram providing an exemplary illustration of theclient device location system of FIG. 6 determining locations of clientdevices based on a plurality of power-regulated UL communicationssignals that is respectively generated by a plurality of remote unitsbased on a plurality of respective reference signal power patterns;

FIG. 8 is a schematic diagram of an exemplary client device locationidentification system that includes a client device location systemconfigured to determine the locations of client devices in a DAS basedon a plurality of power-regulated UL communications signals that isrespectively generated by a plurality of remote unit clusters;

FIG. 9 is a schematic diagram of an exemplary central unit coupled tothe client device location system of FIG. 4, the client device locationsystem of FIG. 6, or the client device location system of FIG. 8 todetermine locations of client devices in a DAS;

FIG. 10A is a schematic diagram providing an exemplary illustration of alocation server configured to locate a specified client device(s)associated with a specified reference signal(s);

FIG. 10B is a schematic diagram providing an exemplary illustration of alocation server configured to locate a specified client device(s)associated with a specified client device identification(s);

FIG. 11 is a schematic diagram of an exemplary DAS in which the clientdevice location system of FIG. 4, the client device location system ofFIG. 6, or the client device location system of FIG. 8 is coupled toboth a central unit and a communications signal source to determinelocations of client devices in the DAS; and

FIG. 12 is a partial schematic cut-away diagram of an exemplary buildinginfrastructure in which the DASs of FIGS. 2, 4, 6, 8, 9, and 11employing the client device location identifications systems can beemployed.

DETAILED DESCRIPTION

Embodiments of the disclosure relate to determining location of clientdevices in a distributed antenna system (DAS) based on detecting uplinkreceived power. In this regard, in aspects disclosed herein, a locationof a client device in a DAS can be identified by determining thelocation of a remote unit with which the client device is engaged indownlink (DL) and/or uplink (UL) communications. In this regard, in oneexemplary aspect, a particular power pattern can be assigned to remoteunits that receive UL communications signals from client devices in theDAS. A remote unit is configured to generate a power-regulated ULcommunications signal based on a respective assigned power pattern andrespective UL communications signals received from client devicesengaged in the UL communications with the remote unit. Thepower-regulated UL communications signal is analyzed in the DAS todetermine if the respective assigned power pattern in the receivedpower-regulated UL communications signal can be associated with a clientdevice to be located. Thus, the location of the client device can beknown to be within a communication range of the remote unit that has therespective assigned power pattern. The remote units in the DAS may eachbe assigned a unique power pattern or share a common power pattern. Whenthe remote units share the common power pattern, the remote units can betemporally controlled to communicate the power-regulated ULcommunications signals in the DAS. By determining the location of theclient device based on detecting the assigned power pattern associatedwith the remote unit communicating with the client device, it ispossible to determine the relative location of the client device in theDAS based on the location of the remote unit, thus providing thelocation of the client device with higher degree of accuracy.

Before discussing examples of determining the locations of clientdevices in a DAS, a discussion of an exemplary DAS that employs acommunications medium to support wireless communications services to aplurality of remote units is first provided with reference to FIG. 1.The discussion of specific exemplary aspects of determining location ofclient devices in a DAS starts at FIG. 2.

In this regard, FIG. 1 illustrates distribution of communicationsservices to remote coverage areas 10(1)-10(N) of a DAS 12, wherein ‘N’is the number of remote coverage areas. These communications servicescan include cellular services, wireless services, such as radiofrequency identification (RFID) tracking, Wireless Fidelity (Wi-Fi),local area network (LAN), and wireless LAN (WLAN), worldwideinteroperability for microwave access (WiMAX), wide-band code-divisionmultiple access (WCDMA), long-term evolution (LTE), and combinationsthereof, as examples. The remote coverage areas 10(1)-10(N) may beremotely located. In this regard, the remote coverage areas 10(1)-10(N)are created by and centered on remote units 14(1)-14(N) (e.g., remoteantenna units) connected to a central unit 16 (e.g., a head-endcontroller, a head-end unit, or a head-end equipment). The central unit16 may be communicatively coupled to a signal source 18, for example, abase transceiver station (BTS) or a baseband unit (BBU). In this regard,the central unit 16 receives downlink communications signals 20D fromthe signal source 18 to be distributed to the remote units 14(1)-14(N).The remote units 14(1)-14(N) are configured to receive the downlinkcommunications signals 20D from the central unit 16 over acommunications medium 22 to be distributed to the respective remotecoverage areas 10(1)-10(N) of the remote units 14(1)-14(N). In anon-limiting example, the communications medium 22 may be a wiredcommunications medium, a wireless communications medium, or an opticalfiber-based communications medium. Each of the remote units 14(1)-14(N)may include an RF transmitter/receiver (not shown) and a respectiveantenna 24(1)-24(N) operably connected to the RF transmitter/receiver towirelessly distribute the communications services to client devices 26within the respective remote coverage areas 10(1)-10(N). The remoteunits 14(1)-14(N) are also configured to receive uplink communicationssignals 20U from the client devices 26 in the respective remote coverageareas 10(1)-10(N) to be distributed to the signal source 18. The size ofeach of the remote coverage areas 10(1)-10(N) is determined by amount ofRF power transmitted by the respective remote units 14(1)-14(N),receiver sensitivity, antenna gain, and RF environment, as well as by RFtransmitter/receiver sensitivity of the client devices 26. The clientdevices 26 usually have a fixed maximum RF receiver sensitivity, so thatthe above-mentioned properties of the remote units 14(1)-14(N) mainlydetermine the size of the respective remote coverage areas 10(1)-10(N).

With continuing reference to FIG. 1, each of the client devices 26typically communicates the uplink communications signals 20U with aremote unit 14 among the remote units 14(1)-14(N). As such, bydetermining the remote unit 14 that receives the uplink communicationssignals 20U, a client device 26 that communicates the uplinkcommunications signals 20U to the remote unit 14 can be identified inthe DAS 12 based on a location of the remote unit 14.

In this regard, FIG. 2 is a schematic diagram of an exemplary clientdevice location identification system 30 that includes a client devicelocation system 32 in a DAS 34. The client device location system 32 isconfigured to determine locations of client devices 36 with respect tolocations of a plurality of remote units 38(1)-38(N) based on detectinga plurality of assigned power patterns 40(1)-40(N) associated with theplurality of remote units 38(1)-38(N), respectively. In a non-limitingexample, each of the plurality of assigned power patterns 40(1)-40(N)represents a UL variable gain power pattern. In another non-limitingexample, an assigned power pattern among the plurality of assigned powerpatterns 40(1)-40(N) may be assigned to one or more RF channels (notshown) associated with a respective remote unit among the plurality ofremote units 38(1)-38(N).

The plurality of remote units 38(1)-38(N), which may be a plurality ofremote antenna units (RAUs), is configured to provide communicationservices in one or more coverage areas 42(1)-42(N), respectively. Eachof the one or more coverage areas 42(1)-42(N) includes one or moreclient devices 36(1)-36(M). In this regard, each of the plurality ofremote units 38(1)-38(N) is configured to communicate a respective DLcommunications signal 44 and a respective UL communications signal 46with the one or more client devices 36(1)-36(M) in a respective coveragearea 42. The respective UL communications signal 46 received by each ofthe plurality of remote units 38(1)-38(N) includes one or more referencesignals 48(1)-48(M) that uniquely identify the one or more clientdevices 36(1)-36(M) communicating the respective UL communicationssignal 46. In a non-limiting example, the one or more reference signals48(1)-48(M) can indicate respective client device identifications of theone or more client devices 36(1)-36(M).

With continuing reference to FIG. 2, in a non-limiting example, each ofthe plurality of assigned power patterns 40(1)-40(N) is a pulse wavethat rises and falls repeatedly according to certain duty cycle. Theplurality of remote units 38(1)-38(N) generates a plurality ofpower-regulated UL communications signals 50(1)-50(N) by increasing anddecreasing power amplitude of the respective UL communications signal 46based on the plurality of assigned power patterns 40(1)-40(N),respectively. Accordingly, each of the plurality of power-regulated ULcommunications signals 50(1)-50(N) will also include the one or morereference signals 48(1)-48(M) that have respective reference signalpower patterns (not shown) corresponding to the assigned power pattern40. The plurality of power-regulated UL communications signals50(1)-50(N) may be received as a combined power-regulated ULcommunications signal 51. The client device location system 32 analyzeseach of the plurality of power-regulated UL communications signals50(1)-50(N) contained in the combined power-regulated UL communicationssignal 51 to determine if any of the respective reference signal powerpatterns associated with the power-regulated UL communications signal 50corresponds to the respective assigned power pattern 40 of the remoteunit 38 that generates the power-regulated UL communications signal 50.By establishing a correlation between the respective reference signalpower patterns associated with the power-regulated UL communicationssignal 50 and the one or more reference signals 48(1)-48(M) included inthe power-regulated UL communications signal 50, the client devicelocation system 32 is able to determine a location of the client device36 based on a location of the remote unit 38 that generates thepower-regulated UL communications signal 50. Alternatively, the clientdevice location system 32 may also determine the location of the clientdevice 36 based on a predefined location surrounding the location of theremote unit 38 that generates the power-regulated UL communicationssignal 50.

With continuing reference to FIG. 2, the client device location system32 includes a client device location controller 52 and a signal analyzer54. The client device location controller 52 determines the plurality ofassigned power patterns 40(1)-40(N) for the plurality of remote units38(1)-38(N), respectively. The client device location controller 52 alsoinstructs the plurality of remote units 38(1)-38(N) to generate theplurality of power-regulated UL communications signals 50(1)-50(N) basedon the plurality of assigned power patterns 40(1)-40(N), respectively.The plurality of remote units 38(1)-38(N) includes a plurality ofvariable gain power amplifiers 56(1)-56(N) that receives the pluralityof assigned power patterns 40(1)-40(N) from the client device locationcontroller 52. The plurality of variable gain power amplifiers56(1)-56(N) is configured to amplify the UL communications signal 46received by each of the plurality of remote units 38(1)-38(N) based onthe plurality of assigned power patterns 40(1)-40(N), thus generatingthe plurality of power-regulated UL communications signals 50(1)-50(N),respectively.

With continuing reference to FIG. 2, the signal analyzer 54 isconfigured to receive the plurality of power-regulated UL communicationssignals 50(1)-50(N) from the plurality of remote units 38(1)-38(N),respectively. For each power-regulated UL communications signal 50 amongthe plurality of power-regulated UL communications signals 50(1)-50(N),the signal analyzer 54 is configured to determine a respective referencesignal power pattern 58 and a respective client device identification 60associated with each of the one or more reference signals 48(1)-48(M)included in the power-regulated UL communications signal 50. In anon-limiting example, the signal analyzer 54 subsequently reports therespective reference signal power pattern 58 and the respective clientdevice identification 60 associated with each of the one or morereference signals 48(1)-48(M) in the power-regulated UL communicationssignals 50 to the client device location controller 52.

In response to receiving the respective reference signal power pattern58 and the respective client device identification 60 associated withthe power-regulated UL communications signals 50, the client devicelocation controller 52 compares the respective reference signal powerpattern 58, which is associated with each of the one or more referencesignals 48(1)-48(M) included in the power-regulated UL communicationssignal 50, against the assigned power pattern 40 of the remote unit 38,which may be any of the plurality of remote units 38(1)-38(N), thatgenerates the power-regulated UL communications signal 50. If therespective reference signal power pattern 58 corresponds to the assignedpower pattern 40 of the remote unit 38 that generates thepower-regulated UL communications signal 50, it is an indication thatthe client device 36 having the respective client device identification60 is communicating with the remote unit 38. Therefore, the clientdevice location controller 52 can report the location of the remote unit38, which generates the power-regulated UL communications signal 50, asa location of the client device 36 having the respective client deviceidentification 60. In this regard, by determining locations of theclient device 36 based on the assigned power pattern 40 of the remoteunit 38 that generates the power-regulated UL communications signal 50,it is possible to locate the client devices 36 relative to the coverageareas 42(1)-42(N), thus providing more accurate locations to supportcontext-aware and location-aware wireless services in the DAS 34.

In a non-limiting example, the DL communications signal 44 may be along-term evolution (LTE) DL communications signal and the ULcommunications signal 46 may be an LTE UL communications signal. In thisregard, the plurality of power-regulated UL communications signals50(1)-50(N) is a plurality of power-regulated LTE UL communicationssignals. As such, the signal analyzer 54 may determine the respectivereference signal power pattern 58 and extract the respective clientdevice identification 60 from one or more LTE Demodulation ReferenceSignals (DRSs) or one or more LTE Sounding Reference Signals (SRSs)included in each of the plurality of power-regulated LTE ULcommunications signals.

FIG. 3 is a flowchart of an exemplary client device locationidentification process 70 that can be employed by the client devicelocation identification system 30 of FIG. 2 to determine client devicelocations in the DAS 34 based on detecting the plurality of assignedpower patterns 40(1)-40(N) associated with the plurality of remote units38(1)-38(N).

With reference to FIG. 3, the client device location system 32 in theclient device location identification system 30 is configured todetermine the assigned power pattern 40 for each of the plurality ofremote units 38(1)-38(N) (block 72). The client device location system32 then configures each of the plurality of remote units 38(1)-38(N) togenerate the power-regulated UL communications signal 50 based on theassigned power pattern 40 (block 74). The power-regulated ULcommunications signal 50 includes the one or more reference signals48(1)-48(M) that uniquely identify the one or more client devices36(1)-36(M) communicating with the remote unit 38 that generates thepower-regulated UL communications signal 50. Subsequently, the clientdevice location system 32 determines the respective reference signalpower pattern 58 and the respective client device identification 60associated with each of the one or more reference signals 48(1)-48(M)included in the power-regulated UL communications signal 50 (block 76).The client device location system 32 then determines whether therespective reference signal power pattern 58 corresponds to the assignedpower pattern 40 of the remote unit 38 that generates thepower-regulated UL communications signal 50 (block 78). The clientdevice location system 32 is further configured to report the locationof the remote unit 38 that generates the power-regulated ULcommunications signal 50 as the location of the client device 36 havingthe respective client device identification 60 if the respectivereference signal power pattern 58 is determined to correspond to theassigned power pattern 40 of the remote unit 38 that generates thepower-regulated UL communications signal 50 (block 80).

As discussed above with regard to the client device locationidentification system 30 in FIG. 2, the client device location system 32determines the locations of the client devices 36 based on the pluralityof assigned power patterns 40(1)-40(N) associated with the plurality ofremote units 38(1)-38(N). The plurality of assigned power patterns40(1)-40(N) can either be identical to each other or be distinct fromeach other. When the plurality of assigned power patterns 40(1)-40(N) isidentical to each other, the client device location system 32 needs tomake sure the plurality of remote units 38(1)-38(N) generates theplurality of power-regulated UL communications signals 50(1)-50(N) allat a same time.

In this regard, FIG. 4 is a schematic diagram of an exemplary clientdevice location identification system 30(1) that includes a clientdevice location system 32(1) configured to determine client devicelocations in a DAS 34(1) based on the plurality of power-regulated ULcommunications signals 50(1)-50(N) that is respectively generated by theplurality of remote units 38(1)-38(N) based on a time-division schedule90. Common elements between FIGS. 2 and 4 are shown therein with commonelement numbers and will not be re-described herein.

With reference to FIG. 4, the client device location identificationsystem 30(1) includes the client device location system 32(1). Theclient device location system 32(1) includes a client device locationcontroller 52(1) and a signal analyzer 54(1). The signal analyzer 54(1)includes a receiver 92 for receiving the combined power-regulated ULcommunications signal 51.

The client device location controller 52(1) determines an assigned powerpattern 94 for the plurality of remote units 38(1)-38(N), respectively.In this regard, in this example, the assigned power pattern 94 isidentical for each of the plurality of remote units 38(1)-38(N). Tounambiguously identify each of the plurality of remote units 38(1)-38(N)based on the assigned power pattern 94, the client device locationcontroller 52(1) in this example also determines the time-divisionschedule 90 for the plurality of remote units 38(1)-38(N). Thetime-division schedule 90 consists of a plurality of specified periods96(1)-96(N) that do not overlap one another. In a non-limiting example,each of the plurality of specified periods 96(1)-96(N) may have durationof two hundred (200) milliseconds (ms) (200 ms). According to thetime-division schedule 90, the client device location controller 52(1)can configure the plurality of remote units 38(1)-38(N) to generate theplurality of power-regulated UL communications signals 50(1)-50(N) basedon the assigned power pattern 94. In a non-limiting example, the clientdevice location controller 52(1) may assign the plurality of specifiedperiods 96(1)-96(N) to the plurality of remote units 38(1)-38(N)according to a round robin scheduling scheme. Alternatively, it may alsobe possible to configure the signal analyzer 54(1) to receive theplurality of power-regulated UL communications signals 50(1)-50(N) basedon the time-division schedule 90. As such, the client device locationcontroller 52(1) can ensure that only one of the plurality ofpower-regulated UL communications signals 50(1)-50(N) is received andanalyzed during each of the plurality of specified periods 96(1)-96(N).The signal analyzer 54(1) may also include a correlation circuit 98configured to correlate the assigned power pattern 94 with a respectivepower pattern carried in each of the plurality of power-regulated ULcommunications signals 50(1)-50(N). Hence, the client device locationcontroller 52(1) can accurately identify the assigned power pattern 94associated with each of the plurality of remote units 38(1)-38(N) ineach of the plurality of specified periods 96(1)-96(N). In anon-limiting example, it may be possible to identify the assigned powerpattern 94 associated with each of the plurality of remote units38(1)-38(N) by detecting and averaging the assigned power pattern 94 inmore than one of the plurality of specified periods 96(1)-96(N), thusfurther improving power pattern detection accuracy.

With continuing reference to FIG. 4, the signal analyzer 54(1) isconfigured to receive the plurality of power-regulated UL communicationssignals 50(1)-50(N) from the plurality of remote units 38(1)-38(N),respectively, during the plurality of specified periods 96(1)-96(N). Foreach power-regulated UL communications signal 50 among the plurality ofpower-regulated UL communications signals 50(1)-50(N) received duringeach specified period 96 among the plurality of specified periods96(1)-96(N), the signal analyzer 54(1) is configured to determine therespective reference signal power pattern 58 and the respective clientdevice identification 60 associated with each of the one or morereference signals 48(1)-48(M) in the power-regulated UL communicationssignal 50 generated during the specified period 96. In a non-limitingexample, the signal analyzer 54(1) subsequently reports the respectivereference signal power pattern 58 and the respective client deviceidentification 60 associated with each of the one or more referencesignals 48(1)-48(M) in the power-regulated UL communications signal 50to the client device location controller 52(1). The signal analyzer54(1) may also report the respective specified period 96 associated witheach of the one or more reference signals 48(1)-48(M) in thepower-regulated UL communications signal 50 to the client devicelocation controller 52(1).

In response to receiving the respective reference signal power pattern58 and the respective client device identification 60 associated withthe power-regulated UL communications signal 50 generated during thespecified period 96 of the time-division schedule 90, the client devicelocation controller 52(1) compares the respective reference signal powerpattern 58 against the assigned power pattern 94 of the remote unit 38,which may be any of the plurality of remote units 38(1)-38(N), thatgenerates the power-regulated UL communications signal 50 during thespecified period 96. If the respective reference signal power pattern 58corresponds to the assigned power pattern 94 of the remote unit 38 thatgenerates the power-regulated UL communications signal 50 during thespecified period 96, it is an indication that the client device 36having the respective client device identification 60 is communicatingwith the remote unit 38 during the specified period 96. Therefore, theclient device location controller 52(1) can report the location of theremote unit 38, which generates the power-regulated UL communicationssignal 50 during the specified period 96 of the time-division schedule90, as the location of the client device 36 having the respective clientdevice identification 60. For example, if the respective referencesignal power pattern 58 corresponds to the assigned power pattern 94 ofthe remote unit 38(1), and the respective client device identification60 is associated with the client device 36(1), the client devicelocation controller 52(1) can report the location of the remote unit38(1) as the location of the client device 36(1). In a non-limitingexample, it may be possible that the client device 36(1) has a previouslocation identified by a location of the remote unit 38(2). In thisregard, the client device location controller 52(1) may take intoconsideration the previous location of the client device 36(1) toimprove accuracy of the location identification.

In another non-limiting example, it may also be possible to moreprecisely locate a client device 36 than by a general locationassociated with one remote unit 38(1)-38(N). For example, if a clientdevice 36 is located in the remote coverage area of more than one remoteunit 38, the client device 36 having the respective client deviceidentification 60 may be associated with one or more reference signals48(1)-48(M) of the one or more power-regulated UL communications signals50 among the plurality of power-regulated UL communications signals50(1)-50(N). In this regard, using client device 36(1) as the example,the client device 36(1) having the respective client deviceidentification 60 may be located in an overlapping coverage area of themore than one remote units 38. This client device 36(1) may be moreprecisely located if the client device 36(1) can be determined to beassociated with the overlapping coverage as opposed to just one remoteunit 38.

In this regard, the client device 36(1) may be located inside theoverlapping coverage area between remote units 38 among remote units38(1)-38(N), such as remote units 38 that are adjacent or closelylocated to each other with overlapping coverage areas. It may also bepossible that the client device 36(1) is located closer to one or someremote units 38(1)-38(N) than the others. In this regard, the clientdevice location controller 52(1) may be configured to provide moreprecise location of the client device 36(1) based on a variety ofmethods.

In another non-limiting example, the client device location controller52(1) may be configured to determine the remote unit 38 among remoteunits 38(1)-38(N) closest to the client device 36(1) by measuring signalstrengths (e.g., received signal strength indicator (RSSI)) of thepower-regulated UL communications signals 50 received by more than oneremote unit 38. This may allow an even more precise determination of thelocation of the client device 36(1) inside the overlapping coverage areain terms of determining which remote unit 38 is located closer to and/orreceiving a stronger power-regulated UL communications signal 50 fromthe client device 36(1). In this regard, the client device locationcontroller 52(1) may be able to determine a remote unit 38 among theremote units 38(1)-38(N) that is closest to the client device 36(1) ifthe power-regulated UL communications signals 50 received by a remoteunit 38 is stronger as compared to the power-regulated UL communicationssignals 50 received by other remote units 38. In another non-limitingexample, the client device location controller 52(1) may be furtherconfigured to determine location of the client device 36(1) by employinga location determination algorithm (e.g., triangulation) to furtherimprove preciseness of the location determination. After determining theone or more associated remote units 38 among the one or more remoteunits 38(1)-38(N), the client device location controller 52(1) mayreport the location of the client device 36(1) associated with one ormore remote units 38 more precisely.

FIG. 5 is a diagram providing an exemplary illustration of the clientdevice location system 32(1) of FIG. 4 determining client devicelocations based on based on the plurality of power-regulated ULcommunications signals 50(1)-50(N) that is respectively generated by theplurality of remote units 38(1)-38(N) based on the time-divisionschedule 90. The plurality of remote units 38(1)-38(N) is configured togenerate the plurality of power-regulated UL communications signals50(1)-50(N) based on the assigned power pattern 94 that is identicalduring each of the plurality of specified periods 96(1)-96(N) of thetime-division schedule 90. During the specified period 96(1), the remoteunit 38(1) generates the power-regulated UL communications signal 50(1)based on the assigned power pattern 94. In the power-regulated ULcommunications signal 50(1), for example, the respective referencesignal power pattern 58 associated with the client device 36(2)corresponds to the assigned power pattern 94 of the remote unit 38(1)that generates the power-regulated UL communications signal 50(1). Assuch, the client device location identification system 30(1) (not shown)can report the location of the remote unit 38(1) as the location of theclient device 36(2).

With continuing reference to FIG. 5, during the specified period 96(2),the remote unit 38(2) generates the power-regulated UL communicationssignal 50(2) based on the assigned power pattern 94. In thepower-regulated UL communications signal 50(2), for example, therespective reference signal power pattern 58 associated with the clientdevice 36(M) corresponds to the assigned power pattern 94 of the remoteunit 38(2) that generates the power-regulated UL communications signal50(2). As such, the client device location identification system 30(1)can report the location of the remote unit 38(2) as the location of theclient device 36(M). Similarly, during the specified period 96(N), theremote unit 38(N) generates the power-regulated UL communications signal50(N) based on the assigned power pattern 94. In the power-regulated ULcommunications signal 50(N), for example, the respective referencesignal power pattern 58 associated with the client device 36(1)corresponds to the assigned power pattern 94 of the remote unit 38(N)that generates the power-regulated UL communications signal 50(N). Assuch, the client device location identification system 30(1) can reportthe location of the remote unit 38(N) as the location of the clientdevice 36(1).

As one alternative to configuring the plurality of remote units38(1)-38(N) to generate the plurality of power-regulated ULcommunications signals 50(1)-50(N) based on the time-division schedule90 in FIG. 4, it is possible to assign unique power patterns to each ofthe plurality of remote units 38(1)-38(N). In this regard, FIG. 6 is aschematic diagram of an exemplary client device location identificationsystem 30(2) that includes a client device location system 32(2)configured to determine client device locations in a DAS 34(2) based ona plurality of power-regulated UL communications signals 50′(1)-50′(N)respectively generated by the plurality of remote units 38(1)-38(N)according to a plurality of assigned unique power patterns 100(1)-100(N)which is distinct among the plurality of remote units 38(1)-38(N) ofFIG. 2. Common elements between FIGS. 2, 4, and 6 are shown therein withcommon element numbers and will not be re-described herein.

With reference to FIG. 6, the client device location identificationsystem 30(2) includes the client device location system 32(2). Theclient device location system 32(2) includes a client device locationcontroller 52(2) and a signal analyzer 54(2). The signal analyzer 54(2)includes the receiver 92 that receives the plurality of power-regulatedUL communications signals 50′(1)-50′(N) as a combined power-regulated ULcommunications signal 51′.

The client device location controller 52(2) determines the plurality ofassigned unique power patterns 100(1)-100(N) for the plurality of remoteunits 38(1)-38(N), respectively. The plurality of assigned unique powerpatterns 100(1)-100(N) is distinct among each other. Accordingly, theclient device location controller 52(2) can configure the plurality ofremote units 38(1)-38(N) to concurrently generate the plurality ofpower-regulated UL communications signals 50′(1)-50′(N) based on theplurality of assigned unique power patterns 100(1)-100(N).

With continuing reference to FIG. 6, the signal analyzer 54(2) isconfigured to concurrently receive the plurality of power-regulated ULcommunications signals 50′(1)-50′(N) from the plurality of remote units38(1)-38(N), respectively. The plurality of power-regulated ULcommunications signals 50′(1)-50′(N) includes a plurality of respectivereference signal power patterns 102(1)-102(N). A correlation circuit 98′correlates the assigned unique power patterns 100(1)-100(N) with theplurality of respective reference signal power patterns 102(1)-102(N)carried in the plurality of power-regulated UL communications signals50′(1)-50′(N). For each power-regulated UL communications signal 50′among the plurality of power-regulated UL communications signals50′(1)-50′(N), the signal analyzer 54(2) is configured to determine therespective reference signal power pattern 102 and a respective clientdevice identification 104 associated with each of the one or morereference signals 48(1)-48(M) (not shown) included in thepower-regulated UL communications signal 50′. In a non-limiting example,the signal analyzer 54(2) subsequently reports the respective referencesignal power pattern 58 and the respective client device identification60 associated with each of the one or more reference signals 48(1)-48(M)in the power-regulated UL communications signal 50′ to the client devicelocation controller 52(2).

In response to receiving the respective reference signal power pattern102 and the respective client device identification 104 associated withthe power-regulated UL communications signal 50′, the client devicelocation controller 52(2) compares the respective reference signal powerpattern 58 against the assigned unique power pattern 100 of the remoteunit 38, which may be any of the plurality of remote units 38(1)-38(N),that generates the power-regulated UL communications signal 50′. If therespective reference signal power pattern 102 corresponds to theassigned unique power pattern 100 of the remote unit 38 that generatesthe power-regulated UL communications signal 50′, it is an indicationthat the client device 36 having the respective client deviceidentification 104 is communicating with the remote unit 38. Therefore,the client device location controller 52(2) can report the location ofthe remote unit 38, which generates the power-regulated ULcommunications signal 50′, as the location of the client device 36having the respective client device identification 104. The clientdevice location controller 52(2) may also report the location of therespective coverage area 42 in which the remote unit 38 is located asthe location of the client device 36 having the respective client deviceidentification 104.

FIG. 7 is a schematic diagram providing an exemplary illustration of theclient device location system 32(2) of FIG. 6 determining locations ofclient devices based on the plurality of power-regulated ULcommunications signals 50′(1)-50′(N) that is respectively generated bythe plurality of remote units 38(1)-38(N) based on the plurality ofrespective reference signal power patterns 102(1)-102(N).

With reference to FIG. 7, in the power-regulated UL communicationssignal 50′(1), for example, the respective reference signal powerpattern 102(1) (not shown) associated with the client device 36(1)corresponds to the assigned unique power pattern 100(1) of the remoteunit 38(1) that generates the power-regulated UL communications signal50′(1). As such, the client device location identification system 30(2)(not shown) can report the location of the remote unit 38(1) as thelocation of the client device 36(1).

As another alternative to employing the time-division schedule 90 forthe plurality of remote units 38(1)-38(N) as discussed in reference ofFIG. 4, it is also possible to first organize the plurality of remoteunits 38(1)-38(N) into multiple remote unit clusters and then employ thetime-division schedule 90 inside each of the multiple remote unitclusters. In this regard, FIG. 8 is a schematic diagram of an exemplaryclient device location identification system 30(3) that includes aclient device location system 32(3) configured to determine clientdevice locations in a DAS 34(3) based on a plurality of power-regulatedUL communications signals 110(1)-110(K) that is respectively generatedby a plurality of remote unit clusters 112(1)-112(K). Elements of FIGS.2, 4, and 6 are referenced in connection with FIG. 7 and will not bere-described herein.

With reference to FIG. 8, each of the plurality of remote unit clusters112(1)-112(K) may be configured to include one or more remote units114(1)-114(L). In a non-limiting example, the plurality of remote unitclusters 112(1)-112(K) is a plurality of logical clusters. In thisregard, it is possible to logically assign the one or more remote units114(1)-114(L) to each of the plurality of remote unit clusters112(1)-112(K) without changing physical locations of the one or moreremote units 114(1)-114(L).

The client device location system 32(3) includes a client devicelocation controller 52(3) and a signal analyzer 54(3). The client devicelocation controller 52(3) determines an assigned power pattern 116 forthe plurality of remote unit clusters 112(1)-112(K), respectively.Accordingly, the plurality of remote unit clusters 112(1)-112(K)generate the plurality of power-regulated UL communications signals110(1)-110(K) based on the assigned power pattern 116. Since theassigned power pattern 116 is identical for each of the one or remoteunits 114(1)-114(L) in each of the plurality of remote unit clusters112(1)-112(K), to be able to unambiguously identify each of the one ormore remote units 114(1)-114(L) in each of the plurality of remote unitclusters 112(1)-112(K) based on the assigned power pattern 116, theclient device location controller 52(3) also determines a time-divisionschedule 118 for the one or more remote units 114(1)-114(L) in each ofthe plurality of remote unit clusters 112(1)-112(K).

The time-division schedule 118 consists of a plurality of specifiedperiods 120(1)-120(L) that do not overlap with each other. In anon-limiting example, each of the plurality of specified periods120(1)-120(L) may have duration of two hundred milliseconds (200 ms).Based on the time-division schedule 118, the client device locationcontroller 52(3) can configure the one or more remote units114(1)-114(L) in each of the plurality of remote unit clusters112(1)-112(K) to generate the power-regulated UL communications signal110 among the plurality of power-regulated UL communications signals110(1)-110(K) based on the assigned power pattern 116. In a non-limitingexample, the client device location controller 52(3) may assign theplurality of specified periods 120(1)-120(L) to the one or more remoteunits 114(1)-114(L) in each of the plurality of remote unit clusters112(1)-112(K) according to round robin scheduling scheme. As such,during each of the plurality of specified periods 120(1)-120(L), onlyone of the one or more remote units 114(1)-114(L) in each of theplurality of remote unit clusters 112(1)-112(K) is generating thepower-regulated UL communications signal 110 among the plurality ofpower-regulated UL communications signals 110(1)-110(K). Hence, theclient device location controller 52(3) can unambiguously identify eachof the one or more remote units 114(1)-114(L) in each of the pluralityof remote unit clusters 112(1)-112(K) based on the assigned powerpattern 116 and the plurality of specified periods 120(1)-120(L).

With continuing reference to FIG. 8, the signal analyzer 54(3) includesa plurality of signal receivers 122(1)-122(K) coupled to the pluralityof remote unit clusters 112(1)-112(K) to receive the plurality ofpower-regulated UL communications signals 110(1)-110(K) as a pluralityof combined power-regulated UL communications signals 124(1)-124(K),respectively. As discussed above, during each of the plurality ofspecified periods 120(1)-120(L), the plurality of combinedpower-regulated UL communications signals 124(1)-124(K) corresponds tothe plurality of power-regulated UL communications signals 110(1)-110(K)that is generated by one of the one or more remote units 114(1)-114(L)in the plurality of remote unit clusters 112(1)-112(K).

The signal analyzer 54(3) is configured to respectively receive theplurality of power-regulated UL communications signals 110(1)-110(K)from the plurality of remote unit clusters 112(1)-112(K) during theplurality of specified periods 120(1)-120(L). The signal analyzer 54(3)is configured to determine the respective reference signal power pattern58 and the respective client device identification 60 associated witheach of the one or more reference signals 48(1)-48(M) (not shown)included in each of the plurality of power-regulated UL communicationssignals 110(1)-110(K) generated during each of the plurality ofspecified periods 120(1)-120(L). In a non-limiting example, the signalanalyzer 54(3) subsequently reports the respective reference signalpower pattern 58 and the respective client device identification 60associated with each of the one or more reference signals 48(1)-48(M) ineach of the plurality of power-regulated UL communications signals110(1)-110(K) during each of the plurality of specified periods120(1)-120(L) to the client device location controller 52(3).

In a non-limiting example, it may be possible to identify the assignedpower pattern 94 associated with each of the plurality of remote unitclusters 112(1)-112(K) by detecting and averaging the assigned powerpattern 116 in more than one of the plurality of specified periods120(1)-120(L), thus further improving power pattern detection accuracy.In another non-limiting example, it may be possible to assign aplurality of assigned unique power patterns 126(1)-126(K) to theplurality of remote unit clusters 112(1)-112(K), respectively. Duringeach of the plurality of specified periods 120(1)-120(L), only one ofthe one or more remote units 114(1)-114(L) in each of the plurality ofremote unit clusters 112(1)-112(K) is generating the power-regulated ULcommunications signal 110 among the plurality of power-regulated ULcommunications signals 110(1)-110(K). By assigning the plurality ofassigned unique power patterns 126(1)-126(K) to the plurality of remoteunit clusters 112(1)-112(K), respectively, it may be possible toincrease the probability of accurately identifying each of the pluralityof remote unit clusters 112(1)-112(K).

In response to receiving the respective reference signal power pattern58 and the respective client device identification 60 associated with apower-regulated UL communications signal 110 among the plurality ofpower-regulated UL communications signals 110(1)-110(K) during aspecified period 120 among the plurality of specified periods120(1)-120(L), the client device location controller 52(3) compares therespective reference signal power pattern 58 against the assigned powerpattern 116 of the remote unit 114, which may be any of the one or moreremote units 114(1)-114(L), that generates the power-regulated ULcommunications signal 110 during the specified period 120. If therespective reference signal power pattern 58 corresponds to the assignedpower pattern 116 of the remote unit 114 that generates thepower-regulated UL communications signal 110 during the specified period120, it is an indication that the client device 36 having the respectiveclient device identification 60 is communicating with the remote unit114 during the specified period 120. Therefore, the client devicelocation controller 52(3) can report the location of the remote unit114, which generates the power-regulated UL communications signal 110during the specified period 120, as the location of the client device 36having the respective client device identification 60.

The client device location system 32(1) of FIG. 4, the client devicelocation system 32(2) of FIG. 6, and the client device location system32(3) of FIG. 8 may be coupled to a central unit of a DAS. In thisregard, FIG. 9 is a schematic diagram of an exemplary central unit 130coupled to the client device location system 32(1) of FIG. 4, the clientdevice location system 32(2) of FIG. 6, or the client device locationsystem 32(3) of FIG. 8 to determine client device locations in a DAS132. Common elements between FIGS. 4, 6, 8, and 9 are shown therein withcommon element numbers and will not be re-described herein.

With reference to FIG. 9, in a non-limiting example, the DAS 132 may bea wireless distribution system (WDS) deployed in a star or a daisy chaintopology and the central unit 130 may be provided as a head-endequipment (HEE). The central unit 130 is communicatively coupled to acommunications signal source 134. In a non-limiting example, thecommunications signal source 134 may be a base transceiver station(BTS), a baseband unit (BBU), a virtual base station (vBS), or acentralized/clouding radio access network (C-RAN). In anothernon-limiting example, the signal analyzer 54(1), the signal analyzer54(2), or the signal analyzer 54(3) may be provided in the central unit130. In another non-limiting example, the central unit 130 may include asignal coupler 136. The signal coupler 136 is configured to receive aplurality of power regulated UL communications signals 138(1)-138(P)from a plurality of remote units 140(1)-140(P), respectively. Thecentral unit 130 is coupled to the plurality of remote units140(1)-140(P) via at least one communications medium 141. In anon-limiting example, the DAS 132 may be an optical fiber-based DAS andthe at least one communications medium 141 is at least one opticalfiber-based communications medium. The signal coupler 136 provides theplurality of power regulated UL communications signals 138(1)-138(P) tothe central unit 130. The central unit 130 provides the plurality ofpower regulated UL communications signals 138(1)-138(P) to the signalanalyzer 54(1), the signal analyzer 54(2), and the signal analyzer54(3).

With continuing reference to FIG. 9, the client device location system32(1), the client device location system 32(2), and the client devicelocation system 32(3) may be respectively coupled to a location server142. In a first non-limiting example, the location server 142 mayinitiate a request 144 to locate a specified client device(s) 146associated with specified reference signal(s) (not shown).Alternatively, in a second non-limiting example, the location server 142may initiate a request 148 to locate the specified client device(s) 146associated with specified client device identification(s) (not shown).In another non-limiting example, the location server 142 may initiatethe request 144 or the request 148 in response to receiving a locationservice request 150 from the communications signal source 134. Forexample, the communications signal source 134 may generate the locationservice request 150 in response to receiving an enhanced-911 (E911) callfrom the specified client device(s) 146. In another non-limitingexample, the location server 142 may be configured to automaticallyupdate locations of the specified client device(s) 146 in the DAS 132according to a specified schedule. In response to receiving the request144 or the request 148 from the location server 142, the client devicelocation systems 32(1), 32(2), and 32(3) may provide a location report152 to indicate location(s) of the remote unit(s), for example theremote unit 140(2), with which the specified client device(s) 146 iscommunicating.

In this regard, FIG. 10A is a schematic diagram providing an exemplaryillustration of the location server 142 of FIG. 9 configured to locatethe specified client device(s) 146 associated with the specifiedreference signal(s). Elements of FIG. 9 are referenced in connectionwith FIG. 10A and will not be re-described herein.

With reference to FIG. 10A, in a non-limiting example, if the specifiedclient device(s) 146 (not shown) is an LTE client device, the locationserver 142 may indicate in the request 144 to locate the specifiedclient device(s) 146 (not shown) associated with specified DRS(s) (notshown) and/or SRS(s) (not shown) in specified physical resource blocks(PRBs) (not shown). In another non-limiting example, the location server142 may request the communications signal source 134 (not shown) toinstruct the specified client device(s) 146 to transmit the specifiedSRS(s) when the specified client device(s) 146 is in idle modeoperation. In another non-limiting example, the specified referencesignal(s) (not shown) for locating the specified client device(s) 146may be provided by the communications signal source 134 in the locationservice request 150 (not shown) and forwarded to the client devicelocation systems 32(1), 32(2), and 32(3) along with the request 144. Inresponse to receiving the request 144, the client device locationsystems 32(1), 32(2), and 32(3) locate the specified client device(s)146 based on the specified reference signal(s) and provide the locationreport 152 to indicate the location(s) of the specified client device(s)146.

FIG. 10B is a schematic diagram providing an exemplary illustration ofthe location server 142 of FIG. 9 configured to locate the specifiedclient device(s) 146 (not shown) associated with the specified clientdevice identification(s) (not shown). Elements of FIG. 9 are referencedin connection with FIG. 10B and will not be re-described herein.

With reference to FIG. 10B, in a non-limiting example, the locationserver 142 may indicate in the request 148 to locate the specifiedclient device(s) 146 associated with specified client deviceidentification(s). In a non-limiting example, the specified clientdevice identification(s) may be cell radio network temporary identifier(C-RNTI), international mobile subscriber identity (IMSI), and so on.

According to previous discussions with references to FIGS. 4, 6, and 8,the client device location systems 32(1), 32(2), and 32(3) can onlylocate the specified client device(s) 146 based on the respectivereference signal power pattern 58 (not shown). As such, the clientdevice location systems 32(1), 32(2), and 32(3) must determine thespecified reference signal(s) (not shown) corresponding to the specifiedclient device identification(s). In a non-limiting example, the clientdevice location systems 32(1), 32(2), and 32(3) may obtain the specifiedreference signal(s) corresponding to the specified client deviceidentification(s) by analyzing the downlink control information (DCI).After determining the specified reference signal(s) corresponding to thespecified client device identification(s), the client device locationsystems 32(1), 32(2), and 32(3) locate the specified client device(s)146 based on the specified reference signal(s) and the specified clientdevice identification(s) to provide the location report 152 indicatingthe location(s) of the specified client device(s) 146.

With reference back to FIG. 9, the client device location system 32(1)of FIG. 4, the client device location system 32(2) of FIG. 6, and theclient device location system 32(3) of FIG. 8 may also be coupled toboth the central unit 130 and the communications signal source 134. Inthis regard, FIG. 11 is a schematic diagram of an exemplary DAS 160 inwhich the client device location system 32(1) of FIG. 4, the clientdevice location system 32(2) of FIG. 6, or the client device locationsystem 32(3) of FIG. 8 is coupled to both a central unit 162 and acommunications signal source 164 to determine client device locations inthe DAS 160. Common elements between FIGS. 9 and 11 are shown thereinwith common element numbers and will not be re-described herein.

As illustrated in FIG. 11, the signal analyzer 54(1) of the clientdevice location system 32(1), the signal analyzer 54(2) of the clientdevice location system 32(2), or the signal analyzer 54(3) of the clientdevice location system 32(3) may also be provided in the communicationssignal source 164. The client device location system 32 of FIG. 2, theclient device location system 32(1) of FIG. 4, the client devicelocation system 32(2) of FIG. 6, or the client device location system32(3) of FIG. 8, which may be provided in the DAS 34 of FIG. 2, the DAS34(1) of FIG. 4, the DAS 34(2) of FIG. 6, the DAS 34(3) of FIG. 8, theDAS 132 of FIG. 9, and the DAS 160 of FIG. 11, may be provided in anindoor environment, as illustrated in FIG. 12. FIG. 12 is a partialschematic cut-away diagram of an exemplary building infrastructure 170in which the DAS 34 of FIG. 2, the DAS 34(1) of FIG. 4, the DAS 34(2) ofFIG. 6, the DAS 34(3) of FIG. 8, the DAS 132 of FIG. 9, and the DAS 160of FIG. 11 can be employed. The building infrastructure 170 in thisembodiment includes a first (ground) floor 172(1), a second floor172(2), and a third floor 172(3). The floors 172(1)-172(3) are servicedby a central unit 174 to provide antenna coverage areas 176 in thebuilding infrastructure 170. The central unit 174 is communicativelycoupled to a base station 178 to receive downlink communications signals180D from the base station 178. The central unit 174 is communicativelycoupled to a plurality of remote units 182 to distribute the downlinkcommunications signals 180D to the plurality of remote units 182 and toreceive uplink communications signals 180U from the plurality of remoteunits 182, as previously discussed above. The downlink communicationssignals 180D and the uplink communications signals 180U communicatedbetween the central unit 174 and the plurality of remote units 182 arecarried over a riser cable 184. The riser cable 184 may be routedthrough interconnect units (ICUs) 186(1)-186(3) dedicated to each of thefloors 172(1)-172(3) that route the downlink communications signals 180Dand the uplink communications signals 180U to the plurality of remoteunits 182 and also provide power to the plurality of remote units 182via array cables 188.

The embodiments disclosed herein include various steps. The steps of theembodiments disclosed herein may be formed by hardware components or maybe embodied in machine-executable instructions, which may be used tocause a general-purpose or special-purpose processor programmed with theinstructions to perform the steps. Alternatively, the steps may beperformed by a combination of hardware and software.

The embodiments disclosed herein may be provided as a computer programproduct, or software, that may include a machine-readable medium (orcomputer-readable medium) having stored thereon instructions, which maybe used to program a computer system (or other electronic devices) toperform a process according to the embodiments disclosed herein. Amachine-readable medium includes any mechanism for storing ortransmitting information in a form readable by a machine (e.g., acomputer). For example, a machine-readable medium includes: amachine-readable storage medium (e.g., ROM, random access memory(“RAM”), a magnetic disk storage medium, an optical storage medium,flash memory devices, etc.), and the like.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps, or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is in no way intendedthat any particular order be inferred.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the invention. Since modifications, combinations,sub-combinations and variations of the disclosed embodimentsincorporating the spirit and substance of the invention may occur topersons skilled in the art, the invention should be construed to includeeverything within the scope of the appended claims and theirequivalents.

What is claimed is:
 1. A wireless communication system for locatingclient devices, comprising: a central unit communicatively coupled to acommunications signal source and a plurality of remote units over atleast one communications medium, wherein each of the plurality of remoteunits is configured to: receive a downlink (DL) communications signalfrom the central unit over the at least one communications medium;distribute the DL communications signal to one or more client devices inthe wireless communication system; receive an uplink (UL) communicationssignal from the one or more client devices; generate a power-regulatedUL communications signal based on an assigned power pattern, thepower-regulated UL communications signal comprising one or morereference signals uniquely identifying the one or more client devices;and provide the power-regulated UL communications signal to the centralunit over the at least one communications medium; and a client devicelocation system communicatively coupled to the central unit and theplurality of remote units, the client device location system configuredto: determine the assigned power pattern for each of the plurality ofremote units; receive the power-regulated UL communications signal fromeach of the plurality of remote units; determine a respective referencesignal power pattern and a respective client device identificationassociated with each of the one or more reference signals comprised inthe received power-regulated UL communications signal; determine whetherthe respective reference signal power pattern corresponds to theassigned power pattern of a remote unit that generates thepower-regulated UL communications signal; and report a location of theremote unit that generates the power-regulated UL communications signalas a location of a client device having the respective client deviceidentification if the respective reference signal power pattern isdetermined to correspond to the assigned power pattern of the remoteunit that generates the power-regulated UL communications signal.
 2. Thewireless communication system of claim 1, wherein the client devicelocation system is further configured to determine the assigned powerpattern for one or more radio frequency (RF) channels associated witheach of the plurality of remote units.
 3. The wireless communicationsystem of claim 1, wherein the client device location system is furtherconfigured to report a predefined location surrounding the remote unitthat generates the power-regulated UL communications signal as thelocation of the client device having the respective client deviceidentification if the respective reference signal power pattern isdetermined to correspond to the assigned power pattern of the remoteunit that generates the power-regulated UL communications signal.
 4. Thewireless communication system of claim 1, wherein the client devicelocation system comprises: a signal analyzer configured to determine therespective reference signal power pattern and the respective clientdevice identification associated with each of the one or more referencesignals comprised in the received power-regulated UL communicationssignal; and a client device location controller configured to: determinethe assigned power pattern for each of the plurality of remote units;determine whether the respective reference signal power patterncorresponds to the assigned power pattern of the remote unit thatgenerates the power-regulated UL communications signal; and report thelocation of the remote unit or a predefined location surrounding theremote unit that generates the power-regulated UL communications signalas the location of the client device having the respective client deviceidentification if the respective reference signal power pattern isdetermined to correspond to the assigned power pattern of the remoteunit that generates the power-regulated UL communications signal.
 5. Thewireless communication system of claim 4, wherein the signal analyzercomprises a receiver configured to receive a combined power-regulated ULcommunications signal comprising a plurality of power-regulated ULcommunications signals received from each of the plurality of remoteunits.
 6. The wireless communication system of claim 1, wherein: inresponse to the respective client device identification being associatedwith the one or more reference signals comprised in more than onepower-regulated UL communications signal received from more than oneremote unit among the plurality of remote units, the client devicelocation system further configured to: determine a location of theremote unit among the more than one remote unit; and report the locationof the determined remote unit as a location of the client device havingthe respective client device identification.
 7. The wirelesscommunication system of claim 6, wherein the client device locationsystem is further configured to determine the location of the remoteunit among the more than one remote unit generating the more than onepower-regulated UL communications signals based on the determining thelocation of the remote unit closest to a previous determine location ofthe client device.
 8. The wireless communication system of claim 6,wherein the client device location system is further configured to:determine an overlapping coverage area among the more than one remoteunit generating the more than one power-regulated UL communicationssignals based on determining the more than one remote unit receivingpower-regulated UL communications signal from the client device; anddetermine the location of the remote unit among the more than one remoteunit generating the more than one power-regulated UL communicationssignals based on determining the location of the remote unit among themore than one remote unit receiving a stronger power-regulated ULcommunications signal from the client device.
 9. The wirelesscommunication system of claim 1, wherein the client device locationsystem is further configured to: determine a time-division schedulecomprising a plurality of specified periods; configure each of theplurality of remote units to generate the power-regulated ULcommunications signal based on the assigned power pattern and thetime-division schedule; receive the power-regulated UL communicationssignal from one of the plurality of remote units during each of theplurality of specified periods; and determine the respective referencesignal power pattern and the respective client device identificationassociated with each of the one or more reference signals comprised inthe received power-regulated UL communications signal generated duringthe specified period.
 10. The wireless communication system of claim 1,wherein the client device location system is further configured to:assign each of the plurality of remote units a unique power pattern togenerate the power-regulated UL communications signal based on theassigned unique power pattern; receive the power-regulated ULcommunications signal from each of the plurality of remote units; anddetermine the respective reference signal power pattern and therespective client device identification associated with each of the oneor more reference signals comprised in the received power-regulated ULcommunications signal.
 11. The wireless communication system of claim 1,wherein: the plurality of remote units is organized into a plurality ofremote unit clusters, each of the plurality of remote unit clusterscomprising one or more remote units among the plurality of remote units;and the client device location system is further configured to:determine a time-division schedule comprising a plurality of specifiedperiods for the one or more remote units comprised in each of theplurality of remote unit clusters; configure the one or more remoteunits in each of the plurality of remote unit clusters to generate thepower-regulated UL communications signal based on the assigned powerpattern and the time-division schedule; receive a plurality ofpower-regulated UL communications signals from the plurality of remoteunit clusters, respectively, during each of the plurality of specifiedperiods; determine the respective reference signal power pattern and therespective client device identification associated with each of the oneor more reference signals comprised in each of the plurality ofpower-regulated UL communications signals during the specified period;and determine whether the respective reference signal power patterncorresponds to the assigned power pattern of the remote unit thatgenerates the power-regulated UL communications signal during thespecified period; and report the location of the remote unit or apredefined location surrounding the remote unit that generates thepower-regulated UL communications signal during the specified period asthe location of the client device having the respective client deviceidentification if the respective reference signal power pattern isdetermined to correspond to the assigned power pattern of the remoteunit that generates the power-regulated UL communications signal duringthe specified period.
 12. The wireless communication system of claim 4,wherein the client device location system comprises: a signal analyzerconfigured to determine the respective reference signal power patternand the respective client device identification associated with each ofthe one or more reference signals comprised in the receivedpower-regulated UL communications signal during the specified period;and a client device location controller configured to: determine thetime-division schedule comprising the plurality of specified periods forthe one or more remote units comprised in each of the plurality ofremote unit clusters; configure the one or more remote units in each ofthe plurality of remote unit clusters to generate the power-regulated ULcommunications signal based on the assigned power pattern and thetime-division schedule; determine whether the respective referencesignal power pattern corresponds to the assigned power pattern of theremote unit that generates the power-regulated UL communications signalduring the specified period; and report the location of the remote unitor the predefined location surrounding the remote unit that generatesthe power-regulated UL communications signal during the specified periodas the location of the client device having the respective client deviceidentification if the respective reference signal power pattern isdetermined to correspond to the assigned power pattern of the remoteunit that generates the power-regulated UL communications signal duringthe specified period.
 13. The wireless communication system of claim 1,wherein: each of the plurality of remote units configured to generate apower-regulated long-term evolution (LTE) UL communications signal basedon the assigned power pattern, the power-regulated LTE UL communicationssignal comprising one or more Sounding Reference Signals (SRSs) uniquelyidentifying the one or more client devices; and the client devicelocation system further configured to: determine the assigned powerpattern for each of the plurality of remote units; receive thepower-regulated LTE UL communications signal from each of the pluralityof remote units; determine a respective SRS power pattern and arespective client device identification associated with each of the oneor more SRSs comprised in the received power-regulated LTE ULcommunications signal; determine whether the respective SRS powerpattern corresponds to the assigned power pattern of the remote unitthat generates the power-regulated LTE UL communications signal; andreport the location of the remote unit or a predefined locationsurrounding the remote unit that generates the power-regulated LTE ULcommunications signal as the location of the client device having therespective client device identification if the respective SRS powerpattern is determined to correspond to the assigned power pattern of theremote unit that generates the power-regulated LTE UL communicationssignal.
 14. The wireless communication system of claim 1, wherein theplurality of remote units each comprises a variable gain power amplifierconfigured to generate the power-regulated UL communications signalbased on the assigned power pattern
 15. The wireless communicationsystem of claim 1, wherein the client device location system is furtherconfigured to: receive a request from a location server for locating aspecified client device associated with a specified reference signal;receive the power-regulated UL communications signal from each of theplurality of remote units; determine the respective reference signalpower pattern and the respective client device identification associatedwith the specified reference signal in the received power-regulated ULcommunications signal; determine whether the respective reference signalpower pattern corresponds to the assigned power pattern of the remoteunit that generates the power-regulated UL communications signal; andreport the location of the remote unit or a predefined locationsurrounding the remote unit that generates the power-regulated ULcommunications signal as the location of the specified client device ifthe respective reference signal power pattern is determined tocorrespond to the assigned power pattern of the remote unit thatgenerates the power-regulated UL communications signal.
 16. The wirelesscommunication system of claim 1, wherein the client device locationsystem is further configured to: receive a request from a locationserver for locating a specified client device associated a specifiedclient device identification; receive the power-regulated ULcommunications signal from each of the plurality of remote units;determine the respective reference signal power pattern and thespecified client device identification associated with each of the oneor more reference signals comprised in the received power-regulated ULcommunications signal; determine whether the respective reference signalpower pattern corresponds to the assigned power pattern of the remoteunit that generates the power-regulated UL communications signal; andreport the location of the remote unit or a predefined locationsurrounding the remote unit that generates the power-regulated ULcommunications signal as the location of the specified client device ifthe respective reference signal power pattern is determined tocorrespond to the assigned power pattern of the remote unit thatgenerates the power-regulated UL communications signal.
 17. A wirelesscommunication system for locating client devices, comprising: aplurality of remote units optically connected over at least one opticalfiber communications medium and distributed over multiple floors of abuilding infrastructure, wherein each of the plurality of remote unitsis configured to: receive an optical downlink (DL) communications signalover the at least one optical fiber communications medium; distributethe DL communications signal to one or more client devices in thewireless communication system; receive an uplink (UL) communicationssignal from the one or more client devices; generate a power-regulatedUL communications signal based on an assigned power pattern, thepower-regulated UL communications signal comprising one or morereference signals uniquely identifying the one or more client devices;and provide the power-regulated UL communications signal over the atleast one optical fiber communications medium; and a client devicelocation system communicatively coupled to the plurality of remoteunits, the client device location system configured to: determine theassigned power pattern for each of the plurality of remote units;receive the power-regulated UL communications signal from each of theplurality of remote units; determine a respective reference signal powerpattern and a respective client device identification associated witheach of the one or more reference signals comprised in the receivedpower-regulated UL communications signal; determine whether therespective reference signal power pattern corresponds to the assignedpower pattern of a remote unit that generates the power-regulated ULcommunications signal; and report a location of the remote unit thatgenerates the power-regulated UL communications signal as a location ofa client device having the respective client device identification ifthe respective reference signal power pattern is determined tocorrespond to the assigned power pattern of the remote unit thatgenerates the power-regulated UL communications signal.
 18. The wirelesscommunication system of claim 17, wherein: in response to the respectiveclient device identification being associated with the one or morereference signals comprised in more than one power-regulated ULcommunications signal received from more than one remote unit among theplurality of remote units, the client device location system furtherconfigured to: determine a location of the remote unit among the morethan one remote unit; and report the location of the determined remoteunit as a location of the client device having the respective clientdevice identification.
 19. The wireless communication system of claim17, wherein the client device location system is further configured to:determine an overlapping coverage area among the more than one remoteunit generating the more than one power-regulated UL communicationssignals based on determining the more than one remote unit receivingpower-regulated UL communications signal from the client device; anddetermine the location of the remote unit among the more than one remoteunit generating the more than one power-regulated UL communicationssignals based on determining the location of the remote unit among themore than one remote unit receiving a stronger power-regulated ULcommunications signal from the client device.
 20. The wirelesscommunication system of claim 17, wherein the client device locationsystem is further configured to report a predefined location surroundingthe remote unit that generates the power-regulated UL communicationssignal as the location of the client device having the respective clientdevice identification if the respective reference signal power patternis determined to correspond to the assigned power pattern of the remoteunit that generates the power-regulated UL communications signal.